Wireless networks are expected to meet people's ever growing demands. As these demands have grown, so too has information and communication technology (ICT) infrastructure's energy consumption and carbon dioxide (CO2) emissions. For instance, it has been estimated that ICT infrastructure consumes three percent of the world wide energy and produce two percent of the world wide CO2 emissions.
Recently, there has been some progress in understanding cooperative spectrum management and cognitive radio network (CRN) management. The possibility for green communications using CRNs and the tradeoff between opportunity and accuracy, which is referred to as the Cooperative Sensing Scheduling (CSS) problem, have started to be explored as well.
By way of general background, cognitive radios (CRs) are able to interact and learn from radio environments, and adaptively change their working parameters (power, bandwidth, frequency, etc.) to dynamically utilize unused primary users' spectrums. Typically, spectral channels are reserved or licensed for specific types of communications and specific types of users (e.g., military, consumer, cellular, television broadcasts, emergency channels, etc.). The terms primary user (PU) and PU channel represent a relationship between a type of user and the type's designated spectral channel. While, the term secondary user (SU) represents a relationship between types of users who are not designated for a specific spectrum and the specific spectral channel (e.g., PU channel). Accordingly, a type of user may be a PU in one instance and a SU in another instance. In CR parlance, “users” refer to devices.
In the United States, the Federal Communications Commission (FCC), and in other parts of the world other agencies (e.g., Ofcom in the United Kingdom) license and allocate spectrum in various bands. The total available spectrum is greater than the total licensed and allocated spectrum Likewise, the available licensed and allocated spectrum is often greater than the demand. However, the allocation and use of the spectrum can create crowding in limited spectral regions. One way to decrease crowding in limited spectral regions is to take users assigned to one spectrum and give them access to an underutilized spectrum. These SUs can, in some cases, utilize the PU channels. For example, a consumer user can utilize a military channel.
Due to its powerful cognitive capabilities, CR opens up a new direction and possibility for green communications. New functionalities introduced in CRN bring unparalleled agility, but at the same time introduce additional power consumption. Overhead, however, includes the spectrum sensing procedure, which is undertaken before secondary users can access the primary user channels.
The above-described conventional techniques are merely intended to provide an overview of some issues associated with current technology, and are not intended to be exhaustive. Other problems with the state of the art may become further apparent upon review of the following detailed description of the various non-limiting embodiments.